PHILADELPHIA (JTA) — Debbie Wasserman Schultz, the Democratic National Committee chairwoman, will not speak at the convention this week, reportedly because of the revelation of emails revealing tensions between the party and the Bernie Sanders campaign.

In a related issue, a top DNC official apologized for an email in which he suggests depicting Sanders, who is Jewish, as an atheist as a means of undercutting him during the primary season.

Sanders, an Independent senator from Vermont, turned in a surprisingly strong primary campaign, and only this month conceded to the front-runner Hillary Clinton, who will this week accept the nomination at the Philadelphia convention.

CNN reported Sunday, a day before the convention launch, that Wasserman Schultz, a Florida congresswoman who is also a standard-bearer for Jewish Democrats, would be “quarantined” during the convention, gaveling it in on Monday but not delivering a speech.

Citing an anonymous Democrat, CNN said Wasserman Schultz’s planned speech was removed in order not to stoke anger in the Sanders camp, especially now that he is working with Clinton to defeat Donald Trump, the Republican nominee.

“U.S. Sen. Bernie Sanders will make it clear that Hillary Clinton is by far superior to Donald Trump on every major issue from economics and health care to education and the environment,” Sanders’ campaign spokesman, Michael Briggs, said in a statement.

The emails, leaked Friday by Wikileaks and apparently from a batch hacked earlier this year by hackers widely reported to be in Russia, show frustration at the DNC with repeated claims by the Sanders campaign that the DNC is not neutral.

The DNC addressed some of the complaints, including adding debates, which Sanders campaigners had complained were few and scheduled for times of poor viewership.

In some instances, staffers contemplated spurring media to negative coverage of Sanders, but it’s not clear if they acted.

Brad Marshall, the DNC’s chief financial officer, in one email to communications director Luis Miranda and deputy community director Mark Paustenbach suggested getting someone to press Sanders on his beliefs during the campaign.

“Does he believe in a God?” Marshall asks in the May 5 email. “He had skated on saying he has a Jewish heritage. I think I read he is an atheist. This could make several points difference with my peeps. My Southern Baptist peeps would draw a big difference between a Jew and an atheist.”

There’s no evidence that the DNC arranged for such an action. Marshall apologized in a Facebook post over the weekend, Politico reported.

“I deeply regret that my insensitive, emotional emails would cause embarrassment to the DNC, the Chairwoman, and all of the staffers who worked hard to make the primary a fair and open process,” he said. “The comments expressed do not reflect my beliefs, nor do they reflect the beliefs of the DNC and its employees. I apologize to those I offended.”

The DNC did not reply to requests for comment. Asked if Wasserman Schultz should resign, Sanders said he had been calling for her replacement for months. Wasserman Schultz’s term ends this week.

Sanders has said he believes in God and has been shaped by his Jewish upbringing. He has identified Pope Francis’ social action as a model for religious practice.

A chief surrogate for Trump, Pastor Mark Burns, came under fire for calling Sanders an atheist and for suggesting the candidate convert to Christianity.

Trump, who has said he hopes to attract disaffected Sanders voters, decried the leaks on Twitter.

“Leaked e-mails of DNC show plans to destroy Bernie Sanders,” he said. “Mock his heritage and much more.”